formula

formula

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  1. Aaronj46

    A722.3 Formula/ Calculation?

    Max resistance for an EV earth rod. Would anyone be able to break the formula down or direct me to a video etc with a sample? I'm booked on the 2921 at the end of the month. I have the 18th & IET 4th edition available if someone could point me to the right place?
  2. W

    what is the formula for calculating PSCC for final circuits?

    hi in college and watched some YouTube videos and read up on things I think I got the right formula but I'm not sure. Zsc= Zesc(or Zdbsc) + (R1+RN) (R1+RN) = milli ohms/metre x length x correction factor and then divide that by 1000 Zesc = Uo divided by PFC Then add together Zesc and (R1+RN)...
  3. S

    GN3 formula confusion...mistake?

    For continuity of ring final conductors it says we can use the r1 to check the expected result for r2, and gives the following formula to use: r2 = (1/ csa of cpc) / (1/ csa of line) x r2 = (csa of line / csa of cpc) x r2. Shouldn't the bold r2's say r1? After all we can't use an unknown to...
  4. H

    Is there a formula for sizing the amps needed for a breaker?

    HI, I have a small shop space with single phase run to a 100amp breaker main, and I bought a few items such as a welder, plasma cutter and a compressor. In order to ensure I select the correct breaker for these devices and any other ones in the future, I was wonder if there is a formula or...
  5. S

    18th Edition Formula Questions - Any Genuine Examples

    Hi, Firstly, sorry if this post is in the wrong sub-forum group; if it is please advise where to place this thread. I've been studying for the 18th Ed. Regs course via XS Training and all is going really well. The only problem is that I've noticed all their practice material/questions haven't...
  6. M

    delta transfomer current

    Hi All, anybody know the formula to find current on delta transformer?
  7. gazdkw82

    RFC cross connect formula

    I may have asked this question before but I forgot what was said and the problem has reered it's ugly head again. I was doing some RFC testing the other day. Did my cross connecting but when I was doing the calcs I kept getting the wrong figure. It seemed I was not pressing = before dividing by...
  8. P

    Any tips ?? Remembering formula

    Hey I’m studying 2365 at college and I’m at the science part now .. any tips on remembering formula or is it just a case of going over and over it till it’s in your head .. any help much appreciated
  9. S

    3 phase motor over current formula

    the apprentice is sitting his am2 and question is on his 3 phase motor which is 5.5kw what is the over current he dont deal with 3 phase what's quickest way to explain to work it out
  10. M

    excel formula Help

    hi all small formula issue can anyone help got the basics can add, multiply, ect copy columns, but need a multiple column (sum) entry. Row a item £ sorted b total £ sum of h-P (sorted) H-P x a = B all good Column 1-200 some headings but overall so I need H1 - H200 column H x A But for the...
  11. U

    Formula 1 Brazil

    Well the season went by rather quick im not a Hamilton fan myself but he is British so im hoping Rosberg gets some sort of problem to enable it to go to the last race to decide the title. Palmer has secured his seat for next year which is good as there will be 2 British drivers on the grid. I am...
  12. Dan

    Formula One Halo - Good or Bad?

    Formula 1 votes against Halo in 2017 - http://www.skysports.com/f1/news/12433/10515016/formula-1-votes-against-halo-in-2017 Not as cool as the auroscreen or whatever the other option was. But that failed FIA tests apparently.
  13. H

    Quick Formula Confirmation

    I've a mock paper to do in preparation of my 202 exam. One of the questions is: A circuit dissipates 7.5kW at a power factor of 0.9 when connected to a 230V a.c. supply. The current flowing in the circuit will be: a) 13.0A b) 29.3A c) 21.5A d) 25.2A Now, this is where I might be loosing my...
  14. V

    Generator formula

    Hi everyone, I am looking to know the formula for KW to Kva and any other related formula that you would know thanks v
  15. M

    Excel formula

    Hi all I know this is a bit of topic just doing excel spread sheet for costing, want to enter amount of stuff in one column & use a cost per 100 as I go along is there a formula, example first row amount of fixings next unit cost per 100 last unit sum of the last 2 ( per 100 units) ?????
  16. Paul.M

    Trainee's & Mentors Thread Ideas???

    After seeing Not_Today's thread asking about what books to buy for the mathematics side of your tuition and speaking with Doody Toody on site today, should we start a "Formula Thread"? I think it would be helpful for a lot of people because the majority of members are L2 or L3 students and at...
  17. Simonslimline

    Frequency - Volts - Amps. A little help please.

    Ok i just spotted this in the main section of the forum and it got me thinking about the answers. I dont remember doing this at college. A reactor allows a current of 15a to flow from a 230v 50 Hz supply. Determine the current which will flow at the same voltage if the frequency changes...
  18. spud1

    Microsoft excel formula for the adiabatic equation?

    Does anyone know the Microsoft Excel 2010 formula entry to achieve the adiabatic equation? Where, for example cell A1 is the prospective fault current, cell A2 is the disconnection time, cell A3 is the k factor and cell A5 is the resultant minimum c.p.c size? Thanks Spud
  19. M

    Parallel cables

    Hi I was give this calculation to do! First have I done it right? And is this the same as calculating parallel circuits? In a 230V DB 7 different circuit give out an installation resistance test of 200, 200, 150,100,50, 25 and 2. I came up with RT= r1+r2+r3+r4+r5+r6+r7 RT = 1/200 + 1/200 +...
  20. P

    kVA - Amps Formula for Three Phase

    Hi gents Just wondering if anyone can advise me on my working out. Have been asked to advise on supply conductor csa for a sub distribution supply. The power requirements are 10kVA 400V supply. I'm used to working with kW power just not sure on kVA - Amps formula which I have used below: - I...

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